The invention provides a chassis for a truck trailer which is particularly adapted for use with a fifth wheel tractor/semi-trailer combination as used for hauling logs.
Prior art logging semi-trailers commonly have a chassis fabricated from a pair of I-beam members spaced apart laterally, and extending between front and rear portions of the trailer. A plurality of transversely extending bunks are spaced apart longitudinally along the twin I-beams at respective stations to support the load thereon. The bunks are cut to provide a T-shaped clearance opening for each I-beam to pass through, and are secured at the required station of the I-beams by welding, while leaving an upper flange portion of the bunk intact. Service conduits, for example electrical and pneumatic conduits, are usually passed along an inner surface of an I-beam, and secured thereto using clips. This is to prevent inadvertent damage from the load, or from a grapple which is commonly used for positioning the load on the trailer, or for removing the load from the trailer. During loading, it is not unusual for the arms of the grapple to interfere with flanges of the beams, particularly the outwardly extending upper flanges. This interference is time consuming and can damage the load, the beam or the grapple itself. In some instances, swinging of the grapple arms relative to the I-beams can damage the service conduits passing along the I-beams, or can damage other components secured to the I-beams. The grapple is prone to snagging or jamming on flanges of the I-beams, thus preventing withdrawl of the grapple. On some trailers, grapple deflectors are secured to the I-beams to deflect the grapple, but this increases cost and weight of the trailer.
From the above, it can be seen that the prior art logging semi-trailer is time consuming to construct, and can be inconvenient when loading and unloading logs using a grapple.